Fabrication and Test of a Curved-Canted-Cosine-Theta Magnet Used for a Laser-Driven Proton Accelerator System

Proton therapy (PT) is a precise and efficient form of radiotherapy that can accurately target lesions to destroy tumor cells while minimizing damage to surrounding healthy tissues. Peking University has initiated a project to develop a laser-driven proton accelerator system. This paper reports a curved Canted-Cosine-Theta (CCT) magnet, which is a critical component in the proton accelerator system. The CCT superconducting magnet was designed with a curved dipole magnet and two quadrupole CCT magnets nested symmetrically at the dipole magnet ends. The curved CCT magnet has a bending radius of 1000 mm, with tilt angles of 30° and 45° for the dipole and quadrupole magnets, respectively. The dipole magnet was used to generate a 2.5T transverse magnetic field in a 63-mm warm bore, and the quadrupole magnets were used to generate a 20T/m gradient magnetic field at both ends of the magnet. The whole magnet was wound with NbTi superconducting wire, with an operating current of 380A. In this paper, the magnet manufacturing process and testing are presented.